For refrigeration cycle systems in air conditioners, there has been proposed that a refrigeration cycle system is provided with a differential pressure-type throttle device instead of a capillary tube as a throttle device. The differential pressure-type throttle device is configured to optimally control a pressure of a refrigerant between an outlet of a condenser and an inlet of an evaporator in order to efficiently operate a compressor in accordance with an outside air temperature. Moreover, in a refrigeration cycle system in which a number of revolutions of the compressor is variable, the differential pressure-type throttle device is also configured to optimally control the pressure of the refrigerant according to the number of revolutions of the compressor from the labor saving point of view. For example, an end of the throttle device to which the refrigerant is introduced is joined to a primary duct connected to the condenser while the other end of the throttle device from which the refrigerant is discharged is joined to a secondary duct connected to the evaporator.
As illustrated in Patent Document 1, for example, the differential pressure-type throttle device comprises: a valve body adjusting the degree of opening on the valve opening of a housing; a guide skirt which has a plurality of holes and guides movement of the valve body; and a coil spring which urges the valve body toward space of the inlet port of the housing. The aforementioned valve opening of the housing is connected to a condenser (a radiator) while an outflow port of the housing is connected to the evaporator.
A portion of the aforementioned guide skirt around the valve body is provide with a plurality of holes constituting a flow channel of the refrigerant. The guide skirt guides movement of the valve body against the urging force of the coil spring through the cylinder outer side surface of the guide skirt extending toward the outflow port of the housing being brought into contact with the inner wall of the housing. Hereby, the valve body stops at the position where forces acting on the valve body through the valve opening of the housing and the outflow port of the housing are balanced. Accordingly, the degree of opening on the valve opening is determined by elastic force that the coil spring gives to the valve body.